1. Field of the Invention
The present invention relates to green-emitting phosphor particles, a method for manufacturing the green-emitting phosphor particles, a color conversion sheet, a light-emitting device, and an image display device assembly.
2. Description of the Related Art
As for a phosphor material for a white-emitting diode (LED), a SrGa2S4:Eu phosphor has been common knowledge. In order to amplify the brightness of the SrGa2S4:Eu phosphor, it is necessary to increase absorption of excitation light through doping with europium (Eu) serving as an emission center at a high concentration. Doping with excessive europium increases the amount of absorption of excitation light, but a problem occurs in that an internal quantum efficiency is reduced due to saturation of concentration of the emission center and, conversely, the brightness is reduced. In general, this is referred to as concentration quenching. Therefore, in the doping with europium, there is an optimum value for the concentration.